TY - JOUR A1 - Rudel, Thomas A1 - Prusty, Bhupesh K. A1 - Siegl, Christine A1 - Hauck, Petra A1 - Hain, Johannes A1 - Korhonen, Suvi J. A1 - Hiltunen-Back, Eija A1 - Poulakkainen, Mirja T1 - Chlamydia trachomatis Infection Induces Replication of Latent HHV-6 JF - PLoS ONE N2 - Human herpesvirus-6 (HHV-6) exists in latent form either as a nuclear episome or integrated into human chromosomes in more than 90% of healthy individuals without causing clinical symptoms. Immunosuppression and stress conditions can reactivate HHV-6 replication, associated with clinical complications and even death. We have previously shown that co-infection of Chlamydia trachomatis and HHV-6 promotes chlamydial persistence and increases viral uptake in an in vitro cell culture model. Here we investigated C. trachomatis-induced HHV-6 activation in cell lines and fresh blood samples from patients having Chromosomally integrated HHV-6 (CiHHV-6). We observed activation of latent HHV-6 DNA replication in CiHHV-6 cell lines and fresh blood cells without formation of viral particles. Interestingly, we detected HHV-6 DNA in blood as well as cervical swabs from C. trachomatis-infected women. Low virus titers correlated with high C. trachomatis load and vice versa, demonstrating a potentially significant interaction of these pathogens in blood cells and in the cervix of infected patients. Our data suggest a thus far underestimated interference of HHV-6 and C. trachomatis with a likely impact on the disease outcome as consequence of co-infection. KW - blood KW - chlamydia KW - chlamydia infection KW - chlamydia trachomatis KW - DNA replication KW - macrophages KW - polymerase chain reaction KW - viral load Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96731 ER - TY - JOUR A1 - Subbarayal, Prema A1 - Karunakaran, Karthika A1 - Winkler, Ann-Cathrin A1 - Rother, Marion A1 - Gonzalez, Erik A1 - Meyer, Thomas F. A1 - Rudel, Thomas T1 - EphrinA2 Receptor (EphA2) Is an Invasion and Intracellular Signaling Receptor for Chlamydia trachomatis JF - PLoS Pathogens N2 - The obligate intracellular bacterium Chlamydia trachomatis invades into host cells to replicate inside a membrane-bound vacuole called inclusion. Multiple different host proteins are recruited to the inclusion and are functionally modulated to support chlamydial development. Invaded and replicating Chlamydia induces a long-lasting activation of the PI3 kinase signaling pathway that is required for efficient replication. We identified the cell surface tyrosine kinase EphrinA2 receptor (EphA2) as a chlamydial adherence and invasion receptor that induces PI3 kinase (PI3K) activation, promoting chlamydial replication. Interfering with binding of C. trachomatis serovar L2 (Ctr) to EphA2, downregulation of EphA2 expression or inhibition of EphA2 activity significantly reduced Ctr infection. Ctr interacts with and activates EphA2 on the cell surface resulting in Ctr and receptor internalization. During chlamydial replication, EphA2 remains active accumulating around the inclusion and interacts with the p85 regulatory subunit of PI3K to support the activation of the PI3K/Akt signaling pathway that is required for normal chlamydial development. Overexpression of full length EphA2, but not the mutant form lacking the intracellular cytoplasmic domain, enhanced PI3K activation and Ctr infection. Despite the depletion of EphA2 from the cell surface, Ctr infection induces upregulation of EphA2 through the activation of the ERK pathway, which keeps the infected cell in an apoptosis-resistant state. The significance of EphA2 as an entry and intracellular signaling receptor was also observed with the urogenital C. trachomatis-serovar D. Our findings provide the first evidence for a host cell surface receptor that is exploited for invasion as well as for receptor-mediated intracellular signaling to facilitate chlamydial replication. In addition, the engagement of a cell surface receptor at the inclusion membrane is a new mechanism by which Chlamydia subverts the host cell and induces apoptosis resistance. KW - membrane proteins KW - chlamydia infection KW - chlamydia trachomatis KW - chlamydia KW - HeLa cells KW - apoptosis KW - host cells KW - membrane receptor signaling Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125566 VL - 11 IS - 4 ER - TY - JOUR A1 - Prusty, Bhupesh K. A1 - Chowdhury, Suvagata R. A1 - Gulve, Nitish A1 - Rudel, Thomas T1 - Peptidase Inhibitor 15 (PI15) Regulates Chlamydial CPAF Activity JF - Frontiers in Cellular and Infection Microbiology N2 - Obligate intracellular pathogenic Chlamydia trachomatis express several serine proteases whose roles in chlamydial development and pathogenicity are not completely understood. The chlamydial protease CPAF is expressed during the replicative phase of the chlamydial developmental cycle and is secreted into the lumen of the Chlamydia-containing vacuole called inclusion. How the secreted protease is activated in the inclusion lumen is currently not fully understood. We have identified human serine peptidase inhibitor PI15 as a potential host factor involved in the regulation of CPAF activation. Silencing expression as well as over expression of PI15 affected normal development of Chlamydia. PI15 was transported into the chlamydial inclusion lumen where it co-localized with CPAF aggregates. We show that PI15 binds to the CPAF zymogen and potentially induces CPAF protease activity at low concentrations. However, at high concentrations PI15 inhibits CPAF activity possibly by blocking its protease domain. Our findings shed light on a new aspect of chlamydial host co-evolution which involves the recruitment of host cell proteins into the inclusion to control the activation of bacterial proteases like CPAF that are important for the normal development of Chlamydia. KW - chlamydia KW - CPAF activation KW - peptidase inhibitor PI15 KW - chlamydial inclusion KW - chlamydia serine proteases Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-196918 SN - 2235-2988 VL - 8 IS - 183 ER - TY - JOUR A1 - Kunz, Tobias C. A1 - Götz, Ralph A1 - Sauer, Markus A1 - Rudel, Thomas T1 - Detection of chlamydia developmental forms and secreted effectors by expansion microscopy JF - Frontiers in Cellular and Infection Microbiology N2 - Expansion microscopy (ExM) is a novel tool to improve the resolution of fluorescence-based microscopy that has not yet been used to visualize intracellular pathogens. Here we show the expansion of the intracellular pathogen Chlamydia trachomatis, enabling to differentiate its two distinct forms, catabolic active reticulate bodies (RB) and infectious elementary bodies (EB), on a conventional confocal microscope. We show that ExM enables the possibility to precisely locate chlamydial effector proteins, such as CPAF or Cdu1, within and outside of the chlamydial inclusion. Thus, we claim that ExM offers the possibility to address a broad range of questions and may be useful for further research on various intracellular pathogens. KW - expansion microscopy KW - chlamydia KW - secreted effectors KW - developmental forms KW - superresolution KW - imaging Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-195716 SN - 2235-2988 VL - 9 IS - 276 ER - TY - THES A1 - Vollmuth, Nadine T1 - Role of the proto-oncogene c-Myc in the development of Chlamydia trachomatis T1 - Die Rolle des proto-onkogenes c-Myc in der Entwicklung von Chlamydia trachomatis N2 - Chlamydia trachomatis, an obligate intracellular human pathogen, is the world’s leading cause of infection related blindness and the most common, bacterial sexually transmitted disease. In order to establish an optimal replicative niche, the pathogen extensively interferes with the physiology of the host cell. Chlamydia switches in its complex developmental cycle between the infectious non-replicative elementary bodies (EBs) and the non-infectious replicative reticulate bodies (RBs). The transformation to RBs, shortly after entering a host cell, is a crucial process in infection to start chlamydial replication. Currently it is unknown how the transition from EBs to RBs is initiated. In this thesis, we could show that, in an axenic media approach, L glutamine uptake by the pathogen is crucial to initiate the EB to RB transition. L-glutamine is converted to amino acids which are used by the bacteria to synthesize peptidoglycan. Peptidoglycan inturn is believed to function in separating dividing Chlamydia. The glutamine metabolism is reprogrammed in infected cells in a c-Myc-dependent manner, in order to accomplish the increased requirement for L-glutamine. Upon a chlamydial infection, the proto-oncogene c-Myc gets upregulated to promote host cell glutaminolysis via glutaminase GLS1 and the L-glutamine transporter SLC1A5/ASCT2. Interference with this metabolic reprogramming leads to limited growth of C. trachomatis. Besides the active infection, Chlamydia can persist over a long period of time within the host cell whereby chronic and recurrent infections establish. C. trachomatis acquire a persistent state during an immune attack in response to elevated interferon-γ (IFN-γ) levels. It has been shown that IFN-γ activates the catabolic depletion of L-tryptophan via indoleamine 2,3-dioxygenase (IDO), resulting in the formation of non-infectious atypical chlamydial forms. In this thesis, we could show that IFN-γ depletes the key metabolic regulator c-Myc, which has been demonstrated to be a prerequisite for chlamydial development and growth, in a STAT1-dependent manner. Moreover, metabolic analyses revealed that the pathogen de routs the host cell TCA cycle to enrich pyrimidine biosynthesis. Supplementing pyrimidines or a-ketoglutarate helps the bacteria to partially overcome the persistent state. Together, the results indicate a central role of c-Myc induced host glutamine metabolism reprogramming and L-glutamine for the development of C. trachomatis, which may provide a basis for anti-infectious strategies. Furthermore, they challenge the longstanding hypothesis of L-tryptophan shortage as the sole reason for IFN-γ induced persistence and suggest a pivotal role of c-Myc in the control of the C. trachomatis dormancy. N2 - Chlamydia trachomatis, ein obligat intrazellul¨ares humanes Pathogen, ist weltweit fu¨hrende Ursache fu¨r infektionsbedingte Erblindung und die h¨aufigste, bakterielle sexuell u¨bertragbare Krankheit. Um eine optimale Replikationsnische zu etablieren, interagiert das Pathogen in tensiv mit der Physiologie der Wirtszelle. Chlamydien wechseln in ihrem komplexen Entwick lungszyklus zwischen den infekti¨osen nicht replizierenden Elementark¨orperchen (EBs) und den nicht infekti¨osen replizierenden Retikulark¨orperchen (RBs), und diese Umwandlung in RBs kurz nach dem Eintritt in die Wirtszelle ist ein entscheidender Prozess in der Infektion, um die Replikation des Bakteriums einzuleiten. Derzeit ist noch nicht bekannt, wodurch diese Transformation von EBs zu RBs eingeleitet wird. In dieser Arbeit konnte gezeigt werden, dass bei einer zellfreien Kultivierung des Pathogens die Aufnahme von Glutamin durch den Erreger entscheidend ist, um den ¨Ubergang von EB zu RB zu initiieren. Vor kurzem wurde Peptidoglykan in den Septen von sich replizierenden Chlamydien nachgewiesen. Fu¨r die Syn these des Peptidoglykans nutzen die Bakterien das aufgenommene Glutamin. Der Glutamin metabolismus wird in infizierten Zellen c-Myc abh¨angig umprogrammiert, um den erh¨ohten Bedarf an Glutamin zu bew¨altigen. Bei einer Chlamydieninfektion wird das Proto-Onkogen c-Myc zur F¨orderung der Glutaminolyse der Wirtszelle u¨ber die Glutaminase GLS1 und den Glutamin Transporter SLC1A5/ASCT2 hochreguliert. Ein Eingreifen in diese metabolische Neuprogrammierung fu¨hrt zu einem reduzierten Wachstum von C. trachomatis. Neben der aktiven Infektion k¨onnen Chlamydien u¨ber einen sehr langen Zeitraum in der Wirtszelle persistieren, wodurch es zur Etablierung von chronischen und wiederkehrenden Infektionen kommt. C. trachomatis verf¨allt bei einem Immunangriff in Persistenz, wenn sie auf das freigesetzte Interferon-γ treffen. Es ist bekannt, dass Interferon-γ den Katabolismus von Tryptophan mittels indoleamine 2,3-dioxygenase (IDO) aktiviert, was zur Bildung von nicht infekti¨osen atypischen Chlamydienformen fu¨hrt. In dieser Arbeit konnte gezeigt werden, dass Interferon-γ den zentralen Stoffwechselregulator c-Myc, der sich fu¨r die Entwicklung und das Wachstum von Chlamydien als essentiell erwiesen hat, in Abh¨angigkeit von STAT1 herunter reguliert. Daru¨ber hinaus zeigte die Analyse des Metabolismus, dass das Pathogen den TCA Zyklus der Wirtszelle umleitet, um die Pyrimidinbiosynthese zu unterstu¨tzen. Die Zugabe von Pyrimidinen oder α-Ketoglutarat hilft den Bakterien den Status der Persistenz teilweise zu u¨berwinden. Zusammengenommen deuten die Ergebnisse auf eine zentrale Rolle der c-Myc induzierten Umprogrammierung des Glutaminmetabolismus und des Glutamins selbst fu¨r die Entwicklung von C. trachomatis hin. Diese Befunde k¨onnten eine Basis fu¨r Strategien gegen eine Infektion darstellen. Weiterhin stellen sie die seit langem bestehende Hypothese des Trypotphanmangels als alleiniger Grund fu¨r die von Interferon-γ induzierte Persistenz in Frage und legen eine zentrale Rolle von c-Myc bei der Kontrolle der C. trachomatis Dormanz nahe. KW - Chlamydia trachomatis KW - Persistence KW - trachomatis KW - chlamydia Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-203655 ER -